4 Socket Blade Server–Which Intel CPU Do You Choose?

UPDATED 7.10.12

Now that Intel has released the 4 socket Sandy Bridge CPU, known as the Intel Xeon E5-4600, how do you know whether you need this processor or the Intel E7-4800 CPU?  This is becoming a common question as more and more people migrate larger sized workloads to 4 socket x86 systems in the attempt to lower overall TCO.  To understand which processor you would need, we must first

examine what the differences are.  Last month, I discussed the details of the Intel Xeon E5-2600 CPU, including its ability to have up to 8 cores per CPU, 24 DIMMs (per 2 socket system) and direct integration of the PCIe lanes into the CPU architecture.  The Intel E5-4600 processor builds off of the E5-2600 environment allowing scalability up to 4 CPUs and 48 DIMMs as well as direct integration of PCIe lanes into the CPU.  The biggest difference between the 2 socket E5-2600 (other than the increase in CPUs and DIMMs) and the 4 socket E5-4600 is that the E5-4600 uses a single Quick Path Interconnect, or QPI, to communicate to its peer CPU, a key differentiator compared to the Intel Xeon E7-4800.  The Intel Xeon E5 family also updates Turbo Boost and adds new Advanced Vector Extentions (AVX), but for the context of this article, I won’t be going into these features in any detail, but I encourage you to click through the links for details.

Intel Xeon E7-4800

Intel’s Xeon E7-4800 is technically in a different “class” of CPUs compared to the E5-4600.  They are both expandable, but the E7-4800 is based on the Intel Westmere-EX CPU and is considered an Enterprise class CPU.  The E7 CPU family has an increased CPU core capacity of up to 10 cores (20 with Intel’s Hyper-Threading feature) and has up to 30MB of last level cache that is sharable across all cores.  The E7 family of CPUs from Intel offers integrated memory controllers with 4 channels with speeds up to 6.4 GT/s and has 4 full-width Intel QuickPath Interconnects linking the 4 CPUs together.

Architecture Comparison

Below is a comparison between the Intel Xeon E5-4600 and the E7-4800 CPU.  In summary, the Intel Xeon E7-4800 wins in max CPU cores, cache, memory density and QPI connections, but the Intel Xeon E5-4600 wins all other categories.

UPDATED 8.7.10 – a few people have commented that the Intel Xeon E7-4800 architecture will scale to 8 CPUs.  This is NOT the case.  The E7-8800 will scale to 8 CPUs but NOT the E7-4800 (reference: http://ark.intel.com/products/53571/Intel-Xeon-Processor-E7-4860-(24M-Cache-2_26-GHz-6_40-GTs-Intel-QPI).  I originally left out this knowledge because I didn’t think it applied to blade servers but since then I’ve been corrected that a Tier 2 hardware vendor has an 8 CPU blade server (which is really 4 blade servers crammed into a 5u chassis).  That being said – it still doesn’t relate to the E7-4800 at the time of this writing, you will not find an 8 CPU blade server offering within any of the blade server vendors who are in the top 4 market share.

Performance Comparison

It doesn’t matter how shiny something is, it all comes down to how it performs.  On paper, the architecture of the Intel Xeon E5-4600 appears to blow away its E7 big brother, but that’s not necessarily the case.  The Intel Xeon E7 family has a long list of RAS (Reliability, Availability and Serviceability) features that you wont’ find in the E5 family.  A few E7 CPU features not found anywhere else include:

• Intel® SMI Clock Fail Over
• Intel® SMI Lane Failover
• Intel® SMI Packet Retry
• Dynamic Memory Migration
• Memory Mirroring: Inter-socket
• Memory Mirroring: Fine Grained Mirroring
• Mirrored Memory Board Hot Add/Remove
• Intel® QPI Clock Fail Over
• Intel® QPI Protocol Protection via CRC (8bit or 16bit rolling)
• Intel® QPI Self-Healing
• Intel® QPI Viral Mode
• OS CPU on-lining (capacity change)
• OS CPU off-lining (capacity change)
• OS Memory On-lining (Capacity change)
• Dynamic/OS IOH On-lining (capacity change)
• Processor Sparing / OS Assisted Processor Socket Migration
• Physical CPU Board Hot Add/Remove
• Memory Board Hot Add – Remove
• Physical IOH Hot Add

If you are interested in finding out what each of these features provide, I encourage you to contact your local Intel rep (or server partner.)  The point, though, is that there are a lot of other pieces that factor into the performance of the server that should be considered when deciding what server CPU you need.  Benchmarks are also a good indicator of which CPU you’ll want to use, but finding a benchmark that compares the Intel E5 family with the Intel E7 is hard to come by – but I’ve got you covered.

Comparing the Intel E7-4780 (10 core, 2.4GHz) with an Intel E5-4650 (8 core, 2.7 GHz), you’ll find that the E5 server outperforms against the E7 server in the following benchmarks:

• CAE
• SPECfp*_rate_base2006
• Numerical Weather
• Financial Services
• Life Sciences
• Linpack AVX
• SPECint*_rate_base2006

The E7 server outperforms the E5 server in the following benchmarks:

• java* Middleware
• OLTP Database
• Enterprise Resource Planning

For details on these benchmarks, you’ll have to go back to your Intel rep – but in summary, the guidance from Intel is as follows:

If you have memory intensive enterprise-level applications, you will want to use the Intel Xeon E7-4800 CPU.  For General Purpose, or High Performance Compute work, go with the Intel Xeon E5-4600.

As always, I welcome any thoughts, comments or arguments.  Leave them in the comment section below or contact me at bladesmadesimple AT gmail.com

Kevin Houston is the founder and Editor-in-Chief of BladesMadeSimple.com.  He has over 15 years of experience in the x86 server marketplace.  Since 1997 Kevin has worked at several resellers in the Atlanta area, and has a vast array of competitive x86 server knowledge and certifications as well as an in-depth understanding of VMware and Citrix virtualization.  Kevin works for Dell as a Server Specialist covering the Global 500 East market.